Here's the joke:
Man to woman: Would you sleep with me for one million dollars?
Man: How about for ten dollars?
Woman: What do you think I am?
Man: We've already established what you are. All we're doing is bargaining about price.
I used to like that joke. But I started thinking about it like an economist. As people who read this blog know, I am an economist. Now, imagine that you offered me one million dollars to be a garbageman for a year. I would take it. But if you offered me $30K for the same time, I wouldn't. The fact that I would take a million to be a garbageman doesn't mean I'm a garbageman. The fact that a woman would take a million dollars to be a prostitute doesn't mean she's a prostitute.